Flat Roof Solutions


Combatting door and window heat loss 

If left uninsulated, as much as 20% heat loss can occur around door and window reveals. This results in both expensive heat loss and damaging exposure to moisture. ROCKWOOL ROCKCLOSE® fire resistant Cavity Closers work to effectively minimise thermal bridging at door and window reveals in cavity wall constructions. 


ROCKWOOL ROCKCLOSE® is an innovative internal wall insulation product that has been developed to solve the longstanding problem of thermal bridging. With greater significance under Part L Building Regulations, it provides a solution to address the potential for heat loss around uninsulated door and window reveals. With Building Regulations requiring that thermal bridges occurring at such junctions are included in the calculation of transmission heat losses, ROCKWOOL ROCKCLOSE®works to combat unnecessary and costly heat loss. It consists of a strip of semi-rigid, non-combustible ROCKWOOL® insulation, bonded to a black polyethylene DPC (to BS 6515). With one width covering most applications, it is handily self-supporting and easy to handle. As a fire-resistant cavity closer, it has one-hour fire integrity and 30 minutes insulation, whilst also helpfully reducing noise pollution ingress. An easy to install product, it is used as work proceeds between the outer masonry leaf and internal closer block before the frames are fitted. 


Not CE Marked

  • An effective damp proof course solution – the ROCKWOOL ROCKCLOSE® product actively minimises thermal bridging at door and window reveals.
  • Programme integration – it is easy to build in as the construction programme proceeds and is suitable for both vertical and horizontal application.
  • Flexible solution – it offers a choice of thickness to best suit each project, as the product can be easily cut on site as required, if the 100mm DPC lap is retained. 
  • Integrity – classified as a fire-resistant cavity closer having been assessed by WFRC (Report No C114334)

Product Properties


Product range and ancillaries

Item number External item number Thickness (mm) Width (mm) Length (mm) Pieces Per Pack Packs Per Pallet
265258 265258 20 100 1200 10 25
265265 265265 30 100 1200 10 25
265266 265266 50 100 1200 10 25

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